Small data transmission (SDT) procedures and failure recovery during an inactive state

Abstract

A computer-readable storage medium stores instructions for execution by one or more processors of a UE. The instructions configure the UE for small data transmission (SDT) in a 5G NR network and cause the UE to perform operations comprising detecting while in an RRC_Inactive state, a radio link failure during a first SDT of UL data to a base station. A secure key for a second SDT is generated based on the radio link failure. A configuration message including an indication of the second SDT is transmitted to the base station. A response message including a UL grant is received from the base station. The UL data is encoded for the second SDT using the secure key. The second SDT is performed using the UL grant while the UE is in the RRC_Inactive state.

What is claimed is: 
     
       1. An apparatus for a user equipment (UE) configured for operation in a Fifth Generation New Radio (5G NR) network, the apparatus comprising:
 processing circuitry, wherein to configure the UE for small data transmission (SDT) in the 5G NR network, the processing circuitry is to:
 detect while in a Radio Resource Control Inactive (RRC_Inactive) state, a radio link failure during a first SDT of uplink (UL) data to a base station; 
 generate a secure key for a second SDT based on the radio link failure; 
 encode a configuration message for transmission to the base station, the configuration message including an indication of the second SDT; 
 decode a response message from the base station, the response message including a UL grant; and 
 encode the UL data for the second SDT, the UL data encoded using the secure key, and the second SDT performed using the UL grant while the UE is in the RRC_Inactive state; and 
 
 a memory coupled to the processing circuitry and configured to store the secure key. 
 
     
     
       2. The apparatus of  claim 1 , wherein the processing circuitry is to:
 decode a second configuration message received from the base station, the second configuration message including at least one next-hop chaining count (NCC) parameter; and 
 generate the secure key for the second SDT using the at least one NCC parameter. 
 
     
     
       3. The apparatus of  claim 1 , wherein the processing circuitry is to:
 decode an RRC Release message from the base station, the RRC Release message including a second secure key for the second SDT, and the RRC Release message is decoded after detecting the radio link failure. 
 
     
     
       4. The apparatus of  claim 3 , wherein the processing circuitry is to:
 encode the UL data for the second SDT, the UL data encoded using the second secure key. 
 
     
     
       5. The apparatus of  claim 3 , wherein the UE is temporarily anchored with a previous base station without relocation of a UE context to the base station, and wherein the second secure key is encoded based on a next-hop chaining count (NCC) parameter from the previous base station, the NCC parameter associated with an SDT that has occurred before the first SDT. 
     
     
       6. The apparatus of  claim 1 , wherein the processing circuitry is to:
 perform a horizontal key derivation to generate the secure key for the second SDT; and 
 encode a count of the horizontal key derivation for transmission to the base station, to trigger synchronization of the generated secure key with the base station. 
 
     
     
       7. The apparatus of  claim 1 , wherein the processing circuitry is to:
 encode the UL data for the second SDT with a packet data convergence protocol (PDCP) service data unit (SDU) level or radio link control (RLC) level that is the same as a PDCP SDU level or an RLC level associated with the first SDT. 
 
     
     
       8. The apparatus of  claim 1 , wherein the processing circuitry is to:
 decode configuration signaling from the base station before detecting the radio link failure, the configuration signaling indicating a robust header compression (RoHC) configuration associated with one or more cells of the base station or a radio access network (RAN) notification area (RNA). 
 
     
     
       9. The apparatus of  claim 8 , wherein the processing circuitry is to:
 perform a RoHC during the second SDT based on a current cell of the UE being part of the one or more cells or the current cell of the UE being within the RNA. 
 
     
     
       10. The apparatus of  claim 1 , further comprising transceiver circuitry coupled to the processing circuitry; and one or more antennas coupled to the transceiver circuitry. 
     
     
       11. A non-transitory computer-readable storage medium that stores instructions for execution by one or more processors of a base station, the instructions to configure the base station for small data transmission (SDT) in a Fifth Generation New Radio (5G NR) network, and to cause the base station to perform operations comprising:
 detecting a radio link failure during a first SDT of uplink (UL) data from user equipment (UE) in a Radio Resource Control Inactive (RRC_Inactive) state; 
 encoding a configuration message for transmission to the UE based on the radio link failure, the configuration message including at least one next-hop chaining count (NCC) parameter; 
 decoding a second configuration message from the UE, the second configuration message including an indication of a second SDT; 
 encoding a response message for transmission to the UE in response to the second configuration message, the response message including a UL grant; and 
 decoding the UL data for the second SDT, the UL data encoded using a secure key based on the at least one NCC parameter, and the UL data received based on the UL grant while the UE is in the RRC_Inactive state. 
 
     
     
       12. The non-transitory computer-readable storage medium of  claim 11 , the operations further comprising:
 encoding a second configuration message for transmission to the UE before detecting the radio link failure, the second configuration message indicating a robust header compression (RoHC) configuration associated with one or more cells of the base station or a radio access network (RAN) notification area (RNA); and 
 decoding the UL data during the second SDT and based on the RoHC configuration. 
 
     
     
       13. A non-transitory computer-readable storage medium that stores instructions for execution by one or more processors of user equipment (UE), the instructions to configure the UE for small data transmission (SDT) in a Fifth Generation New Radio (5G NR) network, and to cause the UE to perform operations comprising:
 detecting while in a Radio Resource Control Inactive (RRC_Inactive) state, a radio link failure during a first SDT of uplink (UL) data to a base station; 
 generating a secure key for a second SDT based on the radio link failure; 
 encoding a configuration message for transmission to the base station, the configuration message including an indication of the second SDT; 
 decoding a response message from the base station, the response message including a UL grant; and 
 encoding the UL data for the second SDT, the UL data encoded using the secure key, and the second SDT performed using the UL grant while the UE is in the RRC_Inactive state. 
 
     
     
       14. The non-transitory computer-readable storage medium of  claim 13 , the operations further comprising:
 decoding a second configuration message received from the base station, the second configuration message including at least one next-hop chaining count (NCC) parameter; and 
 generating the secure key for the second SDT using the at least one NCC parameter. 
 
     
     
       15. The non-transitory computer-readable storage medium of  claim 13 , the operations further comprising:
 decoding an RRC Release message from the base station, the RRC Release message including a second secure key for the second SDT, and the RRC Release message is decoded after detecting the radio link failure. 
 
     
     
       16. The non-transitory computer-readable storage medium of  claim 15 , the operations further comprising:
 encoding the UL data for the second SDT, the UL data encoded using the second secure key. 
 
     
     
       17. The non-transitory computer-readable storage medium of  claim 15 , wherein the UE is temporarily anchored with a previous base station without relocation of a UE context to the base station, and wherein the second secure key is encoded based on a next-hop chaining count (NCC) parameter from the previous base station, the NCC parameter associated with an SDT that has occurred before the first SDT. 
     
     
       18. The non-transitory computer-readable storage medium of  claim 13 , the operations further comprising:
 performing a horizontal key derivation to generate the secure key for the second SDT; and 
 encoding a count of the horizontal key derivation for transmission to the base station, to trigger synchronization of the generated secure key with the base station. 
 
     
     
       19. The non-transitory computer-readable storage medium of  claim 13 , the operations further comprising:
 encoding the UL data for the second SDT with a packet data convergence protocol (PDCP) service data unit (SDU) level or radio link control (RLC) level that is the same as a PDCP SDU level or an RLC level associated with the first SDT. 
 
     
     
       20. The non-transitory computer-readable storage medium of  claim 13 , the operations further comprising:
 decoding configuration signaling from the base station before detecting the radio link failure, the configuration signaling indicating a robust header compression (RoHC) configuration associated with one or more cells of the base station or a radio access network (RAN) notification area (RNA); and 
 performing a RoHC during the second SDT based on a current cell of the UE being part of the one or more cells or the current cell of the UE being within the RNA.